1. Field of the Invention
The present invention relates to a magnetic head provided in, for example, a magneto-optical disk device, and, more particularly, to a magnetic head which is thinner, which can be used to generate a magnetic field more efficiently, etc.
2. Description of the Related Art
FIG. 11 is a partial perspective view of a conventional magneto-optical recording magnetic head (or MO head). FIG. 12 is an exploded perspective view of the core assembly of FIG. 11.
The magnetic head 40 comprises a slider 41 and a core assembly 42. The slider 41 is formed of a nonmagnetic ceramic material, such as calcium titanate (TiCaO.sub.3). The bottom surface of the slider 41 is the recording medium facing surface of the slider 41. The top surface of the slider 41 is supported by a supporting member.
As shown in FIG. 12, a center core 43 of the core assembly 42 has a rectangular parallelepiped shape. Sides cores 44 and 44 are substantially L-shaped cores. One end of the center core 43 and one end of each of the side cores 44 are joined by nonmagnetic materials 45 and 45 at a magnetic gap G.
An electrically conductive coil 47 is wound on a bobbin 46 having a through hole 46a extending from the top surface to the bottom surface of the bobbin 46. The center core 43 is inserted into the through hole 46a. A back core 48 is joined to the center core 43 and the side cores 44 and 44, whereby the core assembly 42 is formed.
The magnetic head 40 of FIG. 11 is a floating-type head. As shown in FIG. 11, a flexure 49, being a thin leaf spring member, is bonded to the top surface 41a of the slider 41. The magnetic head is rockably supported at one end of a gimbal through the flexure 49.
As shown in FIG. 12, by winding the electrically conductive coil 47 on the bobbin 46, and inserting the bobbin 46 with the electrically conductive coil 47 wound thereon onto the center core 43, the coil 47 can be very easily installed on the center core 43. However, this method of installing the coil 47 on the center core 43 gives rise to various problems. For example, a thin magnetic head cannot be produced, and it is difficult to increase the efficiency with which a magnetic field is generated.
As shown in FIG. 12, in order to install the electrically conductive coil 47 onto the center core 43, the height h1 of the bobbin 46 on which the coil 47 is wound needs to be at least equal to the length of the center core 43 received by the hole 46a. In addition, when the length, or the like, of the nonmagnetic materials 45 and 45 provided at one end of the center core 43 is considered, the center core 43 needs to be made long, making it difficult to make the entire magnetic head thin. When the coil 47 is formed of an electrically conductive wire, the number of windings and the winding method varies with heads, so that variations occur in the inductance or other wire properties. Further, in order to increase the efficiency with which the center core 43 supplies a magnetic field to a recording medium, the coil 47 needs to be brought as close as possible to the magnetic gap G. However, the structure of the conventional magnetic head makes it extremely difficult to bring the coil 47 close to the magnetic gap G.
FIG. 13 is a plan view of another conventional magnetic head, as seen from the side thereof opposing the recording medium.
Referring to FIG. 13, reference numeral 50 denotes a plate-shaped core formed of a magnetic material, like the center core 43 and the side cores 44 and 44 of FIG. 12. The recording medium opposing surface of the core has a planar shape, with a coil 51 being directly formed spirally on the opposing surface. The thickness of the magnetic head depends only on the thickness of the core 50 and the thickness of the diametrical portion of the planar coil 51. Therefore, this type of magnetic head is thinner than the magnetic head 40 of FIG. 11. When an alternating current is supplied to the planar coil 51 of the magnetic head of FIG. 13, a magnetic field is generated from a center 52 of the planar coil 51 winding, so that a vertical magnetic field is supplied to a recording medium.
However, since this type of magnetic head does not have a protruding core at a portion thereof where a vertical magnetic field is generated, magnetic field lines generated from the winding center 52 cannot be concentrated, so that the strength of the vertical magnetic field supplied from the winding center 52 to the recording medium becomes very weak. When, in order to strengthen the vertical magnetic field, a large amount of electrical current is supplied to the planar coil 51, heat is produced, so that this type of magnetic head is not a desirable type of magnetic head.
In the magnetic head of FIG. 13, the planar coil 51 is formed directly on the recording medium opposing surface of the plate-shaped core, making it difficult to form the recording medium opposing surface into a floating surface (ABS surface). In addition, when floating capability is reduced and the planar coil 51 is in an exposed state at the recording medium opposing surface cause, for example, dirt to move onto the magnetic head.